Howas have a counterbore in the breech end of the barrel...very much like a Remington. I can only assume that you gunsmith is doing this to eliminate the od of the bolt nose from touching the id of the counterbore. If that is the case, what I don't understand is how it's better for the lugs to contact the sleeve than for the bolt nose to touch the counterbore id. As for holding the bolt body, as to help maintain lug contact, the cocking piece is indeed 90°, so that's much better in this regard than a Remington. Also, JMHO, but sleeving the back and front of the bolt can be done to set the clearance wherever you want it to be. This makes more sense to me, but I'm sure I could learn something.--Mike